Before you put all that $$$$ into it, remember that the wiring is going on 59-60 years old and it might just be time to replace - and you will have modern insulation plus the ability to go to 12VDC with modern negative ground and also be able to install a good stereo, halogen headlights replacing the 6V 'candles', LED taillights (but will need a voltage reducer to operate gauges).